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Performance assessment of part-electric General Aviation aircraft

Verfasser: Kolja Seeckt
Abgabedatum: 27.02.2006
Erster Prüfer: Prof. Dr. Scholz
Zweiter Prüfer: Prof. Dr. Zingel
Externer Betreuer: Dr. Young
University of Limerick

Diplomarbeit

Abstract

A study was undertaken that investigates analytically a change of a General Aviation aircraft’s powerplant from an internal combustion (IC) engine to a hybrid engine consisting of an IC engine plus an electric motor. For this purpose, the motor glider Aeromot AMT 200 Super Ximango was chosen as reference aircraft, and its drag polar and primary performance characteristics (e.g. drag and drag power versus speed, range, endurance) were determined. Afterwards, equations were determined to estimate the masses of the new IC engine and electric motor depending on their type of construction and power output. Furthermore, a tool in form of a Microsoft Excel spreadsheet was created to determine and compare aircraft mass, power demand, energy consumption, energy costs and carbon dioxide (CO2) -emissions of the reference and the hybrid aircraft. This tool can be adapted to different reference aircraft, reference missions, battery types, fuel and electricity costs and power splits between IC engine and electric motor. A first attempt to describe the AMT 200 by means of an idealised parabolic drag polar showed that this leads to very poor results during cruise flight for this type of aircraft. In a second step, another drag polar equation was used, which led to realistic results compared to real aircraft data taken from the AMT 200’s flight manual. Large fractions of electrically produced shaft power lead to large mass penalties of the hybrid aircraft – especially due to a large battery mass. Nevertheless, this thesis’ reference cruise flight mission of 2.5 h flight in 2,500 ft at a speed of 50 m/s (180 km/h, 97 kn), shows a reduction in energy costs and CO2-emissions of an order of magnitude of 50 percent at a 50:50 power split between IC engine and electric motor.